Variable speed bi-directional control mechanism

ABSTRACT

A variable speed bi-directional control mechanism for a longitudinally movable carriage. A shaft rotatable by a handle has a centering or dead-man control, means selected by the direction of rotation of the shaft for determining the direction of movement of the carriage and means for controlling the speed of movement of the carriage. The speed of movement is determined by the amount of rotation of the shaft. The mechanism is advantageously employed in apparatus for manipulating a rail through a straightening machine.

United States Patent 1 Warren.

[111 3,749,935 1 July 31,1973

I5 VARIABLE SREED,Bl-DIRECTIONAL GQNTROL E AN SM;

[75] lnventpr: Loyalj}, Wag-ran, Birmingham, Ala.

[73 l Assignee: United,StatpsSteeLCorporation,

Pittsburgh, P,a.

[221 Filed: Man t flflz [21] Ap pl N0.: 233,176,

ZHfifinlQSg 411949, n m "31am,

Primary Examiner-Herman J. Hohauser AuorneyRalph H. Dougherty [57]ABSTRACT A variable speed bi-directional control mechanism f oralpngitudinzilly movable carriage. A shaft rptatahle. by a han dlc hasaeentering or dead-man cont ol meang e qc e by' hc di e io o t o of hehaftfiqt qtermining the direction of movement; of. the carnage q l, fpr.cqntrolling the p Q11 mnmmrznt; Qfl' hq-qan lag qabs: sgq dl z o mentaiq snmlnadi ay he amnumi Ofi'tQtflIiQIl; fl h aft he mmhminm fsadyamagenns x employed: in QPPMQLM. m: mnfliqfllfllrng as ajh h pugh laight ng machima PATENTED JUl3 1 I975 SHEU 2 0F 3 FIG: 2

Fla 5 VARIABLE SPEED BI-DIRECTIONAL CONTROL MECHANISM This inventionrelates to a mechanism for controlling movement of a carriage.

Although my invention is not thus limited, one application for whichthemechanism is particularly useful is in a rail manipulator such asthat shown in Bullard application Ser. No. 233175 filed of even date.

In the rail straightening operation subsequent to the hot rolling ofrails, an operator physically propels a rail in both directions througha gag press. Mechanical devices to perform this function have long beendesired.

However, the devices developed heretofore have not provided the requiredresponsiveness for the rail straightening operation. The Bullardmanipulator is a rail-mounted carriage that is located at the exit endof a gag press. The carriage has a boommounted manipulator headextending to one side. The head includes a rail clamping and rotatingmechanism for grasping the web of a rail and rotating it about itslongitudinal axis. The apparatus of my invention provides the necessarycontrol for propelling the rail through the gag press. Nevertheless myinvention has general application for controlling the direction andspeed of movement of any carriage which is movable in two directions.

It is the primary object of the subject invention to provide anapparatus that will give instant response to an operator, have fingertipcontrol, will cause a carriage to move at variable speeds and in twodirections .with but a single control lever.

It is also an object to provide the invented mechanism with a dead-mancontrol or instant shutdown control.

In the appended drawings:

FIG. I is an elevation view of a railmanipulator including the inventedvariable speed bi-directional control mechanism.

FIG. 2 is an enlarged top view of a portion of FIG. 1.

FIG. 3 is a plan view of the variable speed bidirectional controlmechanism with the cover removed.

FIG. 4 is a sectional view of the control mechanism taken along linelV-IV of FIG.3.

FIG. 5 is a sectional view of the control mechanism taken along line V-Vof FIG. 3. i

For purposes of illustration FIG. 1 shows a rail manipulator like thatshown and claimed in the aforementioned Bullard application. The machinecomprises a base 10, rails 12 mounted on the base, and a wheeledcarriage 14 which rides on the rails. The carriage is propelled alongthe track by a reversible hydraulic motor 15 which drives a pinion 16which engages a rack 18 mounted on the underside of rail base 20. Thecarriage 14 carries on it a manipulator head 24, a hydraulic tank orreservoir 26, and all of the necessary hydraulic equipment to providepower for the drive motor and the manipulator head 24 The manipulator ismounted at the exit end ofa gag press (not shown) for movement along theline of movement of a rail through the gag press.

As shown in FIG. 5, a handle 100 has a dead-man control or centering cam101 with symmetrical shoulders 102 fixed to thehandle by a key 103 and aset screw 104. A pair of spring loaded plungers 106 extending throughhousing 107 bear against shoulders 102. Spring retainers 108, which areexteriorly threaded, are screwed into the threaded portions of housing107 to the proper depth to create equal com- 1 As shown in FIG/3, abevel gear 112 is fixed to the end of handle and engages a bevel gear I13 which .is fixed to a'shaft 1l4. Shaft 114 also carries carns l 16 and117, and a lever 119 at the opposite end of the shaft from the cams.Cams 116 and 117 control microswitches 120 and 121, respectively. Eachmicroswitch controls one direction of movement of the carriage. Lever119, through a knuckle or clevice 123, is connected to a cable 124 whichoperates a servo valve 125, shown only diagrammatically on a hydraulicpump mounted on the outside of hydraulic tank 26. The servo valve, whichis a device well known in the art, controls the speed at which carriage15 moves along the track.

Movement of the carriage 14 along track 12 is controlledby my variablespeed bi-direction'al control mechanism. In operation, when the operatormoves the handle 100 toward the gag press, carriage 14 moves in thatdirection. The rotation of handle 100 rotates bevel gear 112 whichcauses rotation of bevel gear 113 and with it shaft 114. Cams 1 l6 and l17, fixed to shaft 114, control microswitches 120 and 121 and thus thedirection of the movement of the carriage. The cams are eccentricallyarranged in such manner that only one cam can contact a microswitch atany one time. The amount of rotation of shaft 114 controls the openingof the servo valve 125 connected to cable 124. Thus the farther handle100 is moved from the center position, i.e., the greater angle throughwhich shaft 114 is rotated, up to a maximum of 90, the higher the speedat which the carriage will move. 7

When the straightener releases handle 100, the springs in housing 107cause the plungers 106 to return to their equilibrium position as shownin FIG. 5. This action causes the rotation of shaft 1 14 to a neutralposition stopping the movement of the carriage.

It is readily apparent from the foregoing that I have invented anapparatus whereby manipulation of a single lever controls both the speedand direction of movement of a carriage.

I claim:

1. In a machine which includes a carriage, and variable speed reversibledrive means operatively connected with said carriage for propelling itin either of two directions, the combination therewith of an improvedcontrol mechanism for said drive means, said mechanism comprising:

a rotatable shaft, V

a centering cam rotatable by said shaft having two shoulders arrangedsymmetrically around the axis of the cam,

biasing means bearing against each of said shoulders to maintain saidcam and shaft in a predetermined position when the control mechanism isinoperative,

means for rotating said shaft in both directions from said predeterminedposition,

means operable by movement of said shaft in one direction to causemovement of said carriage in one direction,

means operable by movement of said shaft in the opposite direction tocause movement of said carriage in the opposite direction, and e 4first-named shaft, and a microswitch operable by engagement of saidmicroswitch by said cam.

5. Apparatus according to claim 1 wherein said means to vary the speedof movement of said carriage comrises a second shaft rotatable by saidfirst named shaft, an arm fixed to said shaft, a clevice pivotallyconnected to said arm, a connecting member fastened to,

said clevice, a source of power, and a servo valve on said sourcefastened to said connecting member.

l l t I

1. In a machine which includes a carriage, and variable speed reversible drive means operatively connected with said carriage for propelling it in either of two directions, the combination therewith of an improved control mechanism for said drive means, said mechanism comprising: a rotatable shaft, a centering cam rotatable by said shaft having two shoulders arranged symmetrically around the axis of the cam, biasing means bearing against each of said shoulders to maintain said cam and shaft in a predetermined position when the control mechanism is inoperative, means for rotating said shaft in both directions from said predetermined position, means operable by movement of said shaft in one direction to cause movement of said carriage in one direction, means operable by movement of said shaft in the opposite direction to cause movement of said carriage in the opposite direction, and means operable by movement of said shaft in each direction to vary the speed of movement of said carriage.
 2. Apparatus according to claim 1 wherein said biasing means is a spring-mounted plunger.
 3. Apparatus according to claim 1 wherein said means for rotating said shaft is a handle engaging said shaft.
 4. Apparatus according to claim 1 wherein each of said means to cause movement of said carriage comprises a cam fixed to a second shaft rotatable by said first-named shaft, and a microswitch operable by engagement of said microswitch by said cam.
 5. Apparatus according to claim 1 wherein said means to vary the speed oF movement of said carriage comrises a second shaft rotatable by said first named shaft, an arm fixed to said shaft, a clevice pivotally connected to said arm, a connecting member fastened to said clevice, a source of power, and a servo valve on said source fastened to said connecting member. 